Clues to results could be announced early

Some of the earliest returns in today's US Presidential election could provide big clues about the outcome.

Trends in the race between Democrat Barack Obama and Republican John McCain could become clear soon after the first polls begin to close at 6 p.m. EST (23.00 GMT) in Indiana.

Mr Obama and Mr McCain are locked in a surprisingly tight duel in Indiana, a Midwestern state that has voted Republican in every White House race since 1964. A breakthrough win for Mr Obama, or even a neck-and-neck struggle, would be an encouraging sign of broad strength for the senator from neighbouring Illinois.

But if Mr McCain appears to be cruising to a relatively easy win in Indiana it could signal trouble for Mr Obama, who is challenging Mr McCain in about a dozen states won in 2004 by Republican President George W. Bush.

The first public sign of Democrat John Kerry's loss in 2004 came from a worse-than-expected 20-point blowout in Indiana.

"If Mr Obama wins Indiana, the election is over," Democratic consultant Doug Schoen said. "Even if it's close, within two or three points, it probably suggests a big Mr Obama win nationally. If it's more than four points for Mr McCain, it's going to be wait and see for a while."

The next round of tests is at 7 p.m. EST (midnight GMT) when voting ends in Georgia, parts of Florida and the battleground state of Virginia -another place where Democrats have not won a presidential vote since 1964 but have made gains in recent state-wide races.

"If Mr Obama wins Virginia by a decisive margin, it's a pretty strong suggestion he's going to win the election," Schoen said. "If Mr McCain wins by more than a few points that could suggest movement toward him."

At 7.30 p.m. EST (00.30 GMT tomorrow), polls close in the states of Ohio and North Carolina.

By 8 p.m. EST (01.00 GMT tomorrow), all polls in Florida will be closed. Florida's 27 electoral votes and Ohio's 20 electoral votes are two of the biggest prizes still up for grabs today.

Mr McCain, an Arizona senator who faces a perilous path to gaining the 270 electoral votes he needs to win, essentially has to carry all of those early battleground states to have a realistic chance.